<template>
  <div>
    <input
      ref="excel-upload-input"
      class="excel-upload-input"
      type="file"
      accept=".xlsx,.xls,.csv"
      @change="handleClick"
    />
    <!--    <div-->
    <!--      class="drop"-->
    <!--      @drop="handleDrop"-->
    <!--      @dragover="handleDragover"-->
    <!--      @dragenter="handleDragover"-->
    <!--    >-->
    <!--      Drop excel file here or-->
    <el-button
      :loading="loading"
      style="margin-left: 16px"
      size="mini"
      type="primary"
      @click="handleUpload"
    >
      {{ $t('uploadExcel.batchImport') }}
    </el-button>
    <el-link
      style="margin-left: 16px"
      size="mini"
      type="primary"
      href="/template/email_auth_template.xlsx"
    >
      {{ $t('uploadExcel.downloadTemplate') }}
    </el-link>
    <!--    </div>-->
  </div>
</template>

<script lang="ts">
import XLSX from 'xlsx'
import i18n from '@/lang/index'
export default {
  name: 'UploadExcel',
  props: {
    beforeUpload: {
      required: true,
    },
    onSuccess: {
      required: true,
    },
  },
  data() {
    return {
      loading: false,
      $t: i18n,
      excelData: {
        header: null,
        results: null,
      },
    }
  },
  methods: {
    generateData(header: any, results: any) {
      this.excelData.header = header
      this.excelData.results = results
      this.onSuccess && this.onSuccess(this.excelData)
    },
    handleDrop(e: DragEvent) {
      e.stopPropagation()
      e.preventDefault()
      if (this.loading) return
      if (!e.dataTransfer) return
      const files = e.dataTransfer.files
      if (files.length !== 1) {
        this.$message.error('Only support uploading one file!')
        return
      }
      const rawFile = files[0] // only use files[0]

      if (!this.isExcel(rawFile)) {
        this.$message.error(
          'Only supports upload .xlsx, .xls, .csv suffix files'
        )
        return false
      }
      this.upload(rawFile)
      e.stopPropagation()
      e.preventDefault()
    },
    handleDragover(e: DragEvent) {
      e.stopPropagation()
      e.preventDefault()
      if (e.dataTransfer) {
        e.dataTransfer.dropEffect = 'copy'
      }
    },
    handleUpload() {
      ;(this.$refs['excel-upload-input'] as HTMLInputElement).click()
    },
    handleClick(e: MouseEvent) {
      const files = (e.target as HTMLInputElement).files
      if (files) {
        const rawFile = files[0] // only use files[0]
        this.upload(rawFile)
      }
    },
    upload(rawFile: File) {
      ;(this.$refs['excel-upload-input'] as HTMLInputElement).value = '' // Fixes can't select the same excel
      if (!this.beforeUpload) {
        this.readerData(rawFile)
        return
      }
      const before = this.beforeUpload(rawFile)
      if (before) {
        this.readerData(rawFile)
      }
    },
    readerData(rawFile: File) {
      this.loading = true
      const reader = new FileReader()
      reader.onload = (e) => {
        const data = (e.target as FileReader).result
        const workbook = XLSX.read(data, { type: 'array' })
        const firstSheetName = workbook.SheetNames[0]
        const worksheet = workbook.Sheets[firstSheetName]
        const header = this.getHeaderRow(worksheet)
        const results = XLSX.utils.sheet_to_json(worksheet)
        this.generateData(header, results)
        this.loading = false
      }
      reader.readAsArrayBuffer(rawFile)
    },
    getHeaderRow(sheet: { [key: string]: any }) {
      const headers: string[] = []
      const range = XLSX.utils.decode_range(sheet['!ref'])
      const R = range.s.r
      // start in the first row
      for (let C = range.s.c; C <= range.e.c; ++C) {
        // walk every column in the range
        const cell = sheet[XLSX.utils.encode_cell({ c: C, r: R })]
        // find the cell in the first row
        let hdr = ''
        if (cell && cell.t) hdr = XLSX.utils.format_cell(cell)
        if (hdr === '') {
          hdr = 'UNKNOWN ' + C // replace with your desired default
        }
        headers.push(hdr)
      }
      return headers
    },
    isExcel(file: File) {
      return /\.(xlsx|xls|csv)$/.test(file.name)
    },
  },
}
</script>

<style lang="scss" scoped>
.excel-upload-input {
  display: none;
  z-index: -9999;
}

.drop {
  border: 2px dashed #bbb;
  width: 600px;
  height: 160px;
  line-height: 160px;
  margin: 0 auto;
  font-size: 24px;
  border-radius: 5px;
  text-align: center;
  color: #bbb;
  position: relative;
}
</style>
